Recording data or other information-bearing signals on magnetic tape has been practiced for many years. Some of the track formats on magnetic tape facilitate a so-called serpentine scanning of the tape such that the logical beginning and end of the magnetic tape are at the same physical end of the tape. In a preferred form of the invention, it is desired to employ serpentine scanning of data tracks while providing a close control of head-to-tape lateral positioning.
Such control of head-to-tape lateral positioning is best achieved by relatively servoing the head and tape to position the head laterally to the tape. It is also desired, particularly in view of possible high error rates in magnetic tape, to provide a reliable set of servo tracks on a magnetic tape. Concurrently sensing a plurality of laterally spaced-apart servo tracks provides enhanced reliability using managed signal redundancies.
An important aspect of magnetic tape recording is the ever increasing areal data storage density. While any servo track area reduces the area of any storage medium available for data storage, such servo track areas are necessary to provide reliable data storage and retrieval at higher areal data storage densities. Accordingly, it is desired to provide processing of servo signals from plural servo track areas in a reliable manner. It is also desired to provide position error checking independently of processing redundant position error signals.